1. Field of the Invention
The invention is generally directed to infrastructure management, and, more particularly, to advanced management of a sewer infrastructure.
2. Description of the Related Art
Good water infrastructure management is critical for communities all over the world—not only for quality-of-life reasons, but also for public health reasons. When discussing water infrastructure management, the topic is typically broken down into its three components—what engineers refer to as the “three waters”—drinking water, storm water, and sanitary sewer water (also known as waste water).
There are several key issues with sanitary sewer infrastructure management with which developed countries are currently grappling. Primary among them is aging of the infrastructure itself. Aging may crack pipes or the joints between the pipes, damage manhole structures along streets, or lead to a range of other problems. It is not unusual in major cities for a large percentage, or even a majority, of sewer pipes to be in excess of sixty years old. Before 1950, sewer line pipe and joint materials were not as effective as those used today. Many older pipes and joints are simply failing. In addition, up until the 1970s, many communities in the United States routinely linked their storm water systems and sewer systems together. This is an engineering practice that is now clearly discredited due to its direct relationship in creating now-prohibited Sanitary Sewer Overflows (SSOs) during rainstorms. FIG. 1, from a presentation by Mark Wade at the 2005 North American Society for Trenchless Technology (NASTT) Conference, details the range of problems in aging public sewage infrastructure that can lead to infiltration and inflow of rainwater during storms into what should be a closed sewage system.
Waste water treatment plants and the sewage pipes that feed into them are designed to take a pre-calculated volume of raw sewage from households and businesses for multiple levels of treatment prior to any effluent discharge in order to ensure effective elimination of pathogens, etc. However, during rainstorms breaks in sewer pipes, cracks in joints, and, especially, the linking of storm water and sewer systems, allow storm water to mix in with the raw sewage, leading, in some cases, to multiples of the normal underlying sewage volume. When there is a surge of flow during storm events due to the mingling of storm water with the sewage, the waste water treatment plant spends far more on electricity and chemicals to treat the increased flow. Money is wasted on treating storm water that simply should not be mixed in with the sewage. It is well documented that larger waste water treatment plants can actually spend millions of dollars per year on the chemicals needed to treat these storm-related surges of flow.
Once the increased flow of sewage effluent during storms surpasses the design capacity of the waste water treatment plant, either partially treated or totally untreated sewage is dumped into nearby river, bays, or oceans. These are called SSO events. In 2007—some thirty-five years after the passage of the Clean Water Act—it was estimated that some eight-hundred-fifty-billion gallons of raw sewage were still being dumped into U.S. waterways due to SSOs. It is also estimated that over thirty percent of American rivers and estuaries had one or more impairments to usage in 2007 due to the presence of raw sewage from SSOs. Some large river systems in the U.S. are impaired by raw sewage overflows over twenty-five percent of every year.
In addition to overwhelming the waste water treatment plants and causing SSOs, the increased sewage flow during storms may also overwhelm the local pipes themselves. This can result in sewage backups into nearby residents' or businesses' basements, as well as manholes that blow off and allow raw sewage to run across city streets and yards. This increase of flow into sewers during rain storms is known as the “Infiltration and Inflow” (I/I) problem because it is due to the infiltration of rainwater into what should be a closed sewer system, but which is not, due to either cracking, leaking joints, and/or bad design.
There are two additional related issues that can exacerbate these I/I problems. The first issue is tree roots. Tree roots are very opportunistic. In their search for water and nutrients, they can find and penetrate very small cracks in sewage pipes, and, over time, make these cracks much larger, allowing significant water infiltration. Tree roots may also begin to grow inside the sewer pipes themselves, and over time can significantly block the design flow of the pipes. This contributes heavily to backups during storm events. The second issue that exacerbates I/I problems is the buildup of fats, oil, and grease (known as “FOG”) on the inside of sewer pipes. FOG can act in the same way as tree roots. Over time, fats, oil, and grease build up inside the sewer pipes, especially at turns, junctures, etc. During a storm event, these buildups block the design flow of the pipe. Both of these issues may lead directly to basement sewage backups and/or to raw sewage spilling out of manholes. Note a recent article detailing a raw sewage spill due to tree root growth:
Sewage Spill Closes Santa Barbara Beach, Dec. 4, 2012                A 6,600-gallon sewage spill has temporarily shut a popular Santa Barbara beach adjacent to the city's harbor. Leadbetter Beach will not reopen until tests indicate the water is safe, according to Manuel Romero, Santa Barbara's wastewater collection superintendent. The spill of untreated sewage was spotted Monday morning after a resident called the city to complain about a storm sewer access hole that had been overflowing since noon the previous day. Water from the spill flowed into a storm drain, down cliffs and into the ocean at the beach. City workers on Monday unclogged the sewer, which had been blocked by roots growing into a connecting line.        
Prior to the passage of the Clean Water Act in the early 1970's, little attention was paid to I/I issues in collection systems in the U.S. However, since then, laws have systematically been passed that emphasize the elimination of sewer system overflows, and penalties for SSOs have steadily increased. Simultaneously, there has been less funding available to simply build bigger treatment plants or bigger holding tanks for temporary storm surge storage. Building a much larger, very costly, treatment plant or holding tanks designed to handle multiples of the normal volume of sewage flow for storms that only occur a few times a year simply does not make good economic sense.
This growing regulatory pressure to minimize SSOs has led to improved technical competence, inspection tools, and repair methodologies to support basic sewer system maintenance and retrofitting in order to minimize and/or eliminate I/I issues. At the heart of good sewer maintenance practice is the ability to accurately inspect and evaluate the condition of sewer mains, junctures between pipe sections, manholes, laterals feeding into sewer mains, etc., find out where rainwater may be leaking in, and find out where tree roots or FOG may be blocking flow. An accurate assessment of conditions allows for cost effective targeting of needed repairs, which may range from spot grouting to relining of pipes, laterals, and/or joints to actual replacement of entire pipe segments. A wide variety of inspection techniques exist now, as do a multitude of repair techniques. There has been steady growth in these techniques over the last twenty years.
What has been lacking in the field to date is an effective way of coordinating the whole process between city engineers, whoever is doing the inspections, and the parties doing the repairs. For example, the leading method of sewer pipe inspection today is to insert a video camera connected to a closed-circuit television (CCTV) system down a sewer manhole, while inspection personnel narrate the conditions in real time as they see them, noting cracks, leaks, roots, FOG, and other blockages. Under industry practice today, the resulting videos are typically burned to DVDs and handed to an engineer employed (or hired) by the sewer owner—most often a city or other municipal agency—for review. The engineer then plays each video back on a DVD player, making notes that correspond to the number of feet from the originating manhole that a fault or other observation is located. The engineer will then take his notes, find the relevant section of the city's plat maps, and, measuring on the map from the originating manhole, try to manually figure out and mark on the plat map where the sewer pipe fault is. The plat map will then typically get faxed to the people responsible for making (or bidding on) the repair—often a specialty contractor. The contractor will then try to get more information on that section of pipe from the city (e.g., material, size, age, etc.), go to that section of the city on the plat map, try to find the right manhole, run his own camera down the line, and try to find the fault noted on the plat map. Sometimes contractors will receive a copy of the original inspection DVD so that they can see what the fault looks like. The bottom line is that the contractor will attempt to find the same crack or leaking joint or blockage in the sewer and fix it. A post-repair video of that sewer pipe may then be taken, which the engineer will then review on DVD to try to find the same linear foot marker from the originating manhole to verify that the repair has been completed. At some point the city engineer will review paper forms and approve payment both to the contractor who made the inspection videos and to the contractor who repaired the fault. The city engineer will also typically try to make notes as to which sections of the sewer pipe have root growth, which sections need to be cleaned more frequently, and which sections need to be relined or replaced altogether, so that he can build reliable budgets for work in upcoming years. All of the processes outlined above are currently performed manually for the most part, and involve huge amounts of back and forth with paper, trying to find needed information, trying to locate the same fault, etc.
Accordingly, there is an advantage to automating or facilitating automation of this workflow to make it more effective and efficient. Doing so would free up dollars that are currently wasted on manual, paper-based or DVD-based workflows to be spent on repair activities that directly reduce I/I. Thus, embodiments of the systems and methods disclosed herein are intended to address these problems in conventional techniques that result, for example, from the requirements of multiple layers of communication and collaboration.
The first layer of the problem addressed by certain embodiments disclosed herein is that cities and communities have wide variance in their waste water system records—in the kind of information they track, the quality of that information, and the completeness of the information. There are also difficulties in knowing precisely the accurate location of a particular asset, because many cities still are using mapping systems that predate Global Positioning System (GPS) technology. Many smaller cities may only have “as-built” plans for their sewers, which typically reflect the original engineering design plan or blueprint for the sewer construction. Some may be in paper format only, although most are in what is known as Computer-Aided Design (CAD) format. CAD software is able to generate sophisticated engineering drawings, but traditionally such drawings do not have good database record structures. Thus, the as-built or CAD drawings cannot be updated with repairs, changes, etc., because they lack the database structure to do so.
Larger or more sophisticated cities may have transferred some or all of this as-built information from CAD drawings into what are known as asset management systems. Asset management systems are true software database programs with record structures useful for tracking and updating specific information about the components making up the sewer systems, as well as the repair history or changes to those components. However, for those cities with asset management programs for their sewer infrastructure, those working in the field find that every city tends to track different information about their sewer systems in these databases, using different table structures, indexes, and naming formats. The way one city tracks its waste water assets may not at all match how another city tracks those same types of assets. Additionally, the information tracked typically suffers from varying degrees of completeness, and frequently is not kept up-to-date in any standardized way. Finally, the information tends to be confusing and to degenerate towards inaccuracy at a very basic level. How does a contractor or engineer distinguish between one pipe segment at one particular location in a city from the ten thousand other segments that are just like it? How does one engineer communicate to another engineer or contractor precisely where a particular crack is in a particular segment of pipe so that the second engineer can instantly go to that same spot, see the same problem, and fix it? And how can the first engineer find the same spot again and verify that the original problem was solved? Conventional asset management software has not addressed these location issues effectively.
Geospatial software programs can be used to link geospatial location information to asset information. To date, these programs have tended to not be particularly strong on the asset detail record side and/or on the workflow coordination side. In addition, for many of these programs, the geospatial locations of the assets have been derived from the original CAD drawings, which is very problematic. In general, the accuracy of the geospatial coordinates for the involved assets cannot be relied on for damage prevention or advanced asset management practices. Currently, there is an unmet need to blend the strengths of an asset management program with a geospatial program in a manner that allows a platform to address all of these issues in order to create a uniform framework of assets and locations that can be quickly and accurately communicated to all parties and used efficiently as an online workflow platform.
As mentioned previously, many states and cities have relied for years on CAD mapping systems, which have traditionally used what are known as plane coordinate systems for mapping infrastructure locations. Plane coordinate systems predate GPS, having been developed in the 1920s. At the time, they were considered a big jump forward for taking points from the Earth's surface or from engineering design drawings and projecting them onto a flat map. However, they are inherently flawed in that they get increasingly inaccurate as one moves away from their foundational zero points. Plane coordinate systems use a Cartesian grid system of x and y values, and have constant lengths, angles, and areas across two dimensions. These two-dimensional systems are not a match for the curved surface and actual three-dimensional terrain of the Earth. The location of an asset, as identified by a CAD system, and the actual, physical location of the asset in reality can be very different, sometimes off by fifty meters, a hundred meters, or more. This is at the core of why there can be such a mismatch between CAD drawings used for sewage (or other) infrastructure and physical reality. The farther one gets from the control point that was used as the zero point in a plane coordinate system, the greater the cumulative inaccuracy. In addition, it is fairly typical for cities and utilities in a particular geographic area to use different plane coordinate systems in their CAD systems and as-built drawings. So not only do the as-built drawings not match physical reality, but they frequently do not agree with each other. On a practical level, for the engineers and workers in the field, this means that it can be extraordinarily difficult to see where other infrastructure (e.g., a gas distribution line or a fiber optic line) is in relationship to a sewer line or other sewer infrastructure, or to communicate precisely where a particular fault is located so that it can be evaluated and ultimately fixed.
Accordingly, what is needed is a system or method that makes sanitary sewer or waste water infrastructure management more efficient and cost effective, while simultaneously reducing unintended raw sewage overflows from sewers into public waterways.